The present invention relates to a forceps plug for endoscopes, and more particularly, to a forceps plug for endoscopes which is to be fitted into a forceps plug holding frame provided on an endoscope operation body to form an opening for inserting and withdrawing medical treatment instruments to retain a seal of the opening.
As is well known, a forceps plug holding frame which forms an opening for inserting instruments for medical treatment, biopsy and the like into a forceps channel is provided on an endoscope operation body to fit a forceps plug thereinto.
Specifically, as shown in FIG. 1, a forceps plug holding frame 4 is integrally provided on an operation body 3 of an endoscope 2 and a forceps plug 1 for endoscopes is fitted in the frame 4. An opening for medical treatment instruments is formed on the frame 4 and is in communication with a forceps channel formed by a tube for channels (not shown) disposed through the operation body 3 and a body cavity insertable portion 5.
As is well known, the forceps plug 1 hermetically seals the forceps channel against the exterior at an opening thereof during operations such as suction and opens the opening when a medical treatment instrument, an injection pipe for introducing fluids or the like is inserted. In addition, FIG. 1 shows an eyepiece 6, a suction pipe 7 and a suction apparatus 8.
In the past, the forceps plug 1 for endoscopes of the type described above, as shown in FIGS. 2 and 3, comprises an elastic member made of rubber or the like of an M-shaped configration in a longitudinal section and having a slit 9 for insertion in a diametrical direction at the central bottom wall portion of a spherical recess 1a is provided in the upper central part thereof. The slit 9 is to be normally closed by placing both its side walls into close contact with each other under its resilience. The plug 1 is removably and resiliently fitted in the opening of the frame 4. When a forceps 10 for biopsy or the like is inserted into the opening of the frame 4, as shown in FIG. 2, a tip of the forceps 10 is introduced into the slit 9 against its resilience. At this time, since both side walls of the slit 9 are resiliently placed into close contact with each other, a seal against the exterior can be retained. In addition, in the conventional forceps plug described above, there have been proposed that a wall thickness of the slit portion is changed in order to further improve a seal (Japanese Laid-open Patent Application No. Sho 61/1986-131723) and the inner periphery of the plug holding frame is placed into close contact with or pressed to the whole outer periphery of the slit portion in an elastic plug body in order to prevent reduction of the close contact due to yielding of the elastic plug body (Japanese Laid-open Utility Model Application No. Sho 61/1986-57901).
As such, although various measures have been devised to assure a seal of a forceps plug, since medical treatment instruments, injection pipes and the like are frequently inserted in or withdrawn from channels of an endoscope by spreading the slit to perform medical treatment and supply of fluids and medicines, the close tightness of the slit may be reduced due to wear and yielding, thus deteriorating effectiveness as a seal. As a result, when a suction operation is effected, air is drawn in from the exterior to lower the suction capability at the tip of a channel, to leak filth sucked in from a patient body to the exterior through the slit and to pollute an operator by spurting out filth within a bronchial tube when a patient has a coughing fit with a bronchoscope. In addition, in order to prevent lowering sealing effectiveness due to wear and yielding in a slit portion of an elastic plug body, it is conceivable that a thickness of the slit portion is increased or an inner periphery of a plug holding frame is placed into closer contact with or more pressed to the whole outer periphery of the slit portion. With these measures, however, although sealing at the slit may be improved, the opening capability of the slit would be deteriorated. As a result, the insertability of medical treatment instruments and injection pipes also would be deteriorated to result in breakage of the instruments and difficulty in introducing fluids.